Critics of St. Petersburg’s proposed new pier are considering whether to file a petition ahead of a crucial City Council vote Thursday after a guarantee from Mayor Bill Foster that a referendum on the pier would be on the Aug. 27 primary ballot.

Foster made that guarantee in an email sent Thursday to Bud Risser, one of the leaders of Concerned Citizens of St. Petersburg, a political action committee opposed to the futuristic new $50-million pier known as the Lens.

The likelihood of a citywide vote on the project, though, seems unlikely to sway City Council members from moving ahead with the project and authorizing a $1.5-million payment on the next phase of the Lens design.

Council members Jim Kennedy and Steve Kornell, regarded as crucial swing votes on the issue, said Monday they likely will not vote for a delay.

“It’s a bad precedent to say any time there’s an election we should stop,” Kornell said. “‘Stop the Lens’ is not a plan we can build on our waterfront. I’ve listened carefully, and I haven’t heard an alternative plan.”

Leaders of Concerned Citizens say they have collected 21,000 signatures for their Stop the Lens campaign, more than the city charter requires to force a special election on the controversial project.

The group, though, has delayed filing the petition to ensure the referendum is added to the Aug. 27 primary election ballot, when Foster and four council seats are up for re-election and voter turnout likely would be higher than for a special election.

Including the referendum on the primary ballot would save the city about $269,000, the cost of holding a separate mail ballot, according to the Pinellas County Supervisor of Elections Office.

The group is consulting its attorneys before making a decision on whether to act on Foster’s guarantee, Risser said. That caution is, in part, to ensure there is no legal challenge to the referendum process from Lens supporters.

“We appreciate his initiative, and we are doing our necessary due diligence before we can respond,” Risser said.

Foster, who has publicly supported the Lens, also has wanted to avoid the cost of a special election. He did not return calls Monday to discuss his offer to Risser’s group.

Envisioned as an iconic centerpiece of the city’s rejuvenated waterfront, the Lens has stirred considerable controversy, which intensified last summer, when the city rejected a petition submitted by residents of another group trying to save the inverted pyramid pier.

That led to the city being sued by former Councilwoman Kathleen Ford, who is running against Foster. She lost the case but is appealing the ruling in appellate court.

Uncertainty over the project’s future has also divided the City Council, with some members arguing it makes no sense to risk taxpayer dollars for a project that voters could derail.

The Lens’ supporters on council counter that the public had plenty of opportunities to have a say on the project at dozens of public meetings over the last five years and that a detailed design would answer many of the questions raised by critics.

Based on earlier public pronouncements, council members Wengay Netwon, Charlie Gerdes and Chairman Karl Nurse are expected to vote to put the project on hold.

Fellow council members Jeff Danner, Leslie Curran and Bill Dudley have remained staunch advocates of the Lens. Kornell and Kennedy’s votes would allow the Lens to move forward.

Stopping the project would be disrespectful to the people who participated in dozens of public meetings to select the Lens, kennedy said Monday.

“You can’t stop moving forward just because people question what we did,” Kennedy said. “When it comes down to it, I don’t think they have as much real support as they claim from the polls.”